---
title: "Buy one, get one (BOGO): definition and formula"
description: "Buy a unit and get a second free. The price of one order pays the costs of two units, so it works out as a 50% discount on a two-pack."
url: https://offersuite.io/glossary/buy-one-get-one
updated: 2026-10-13
---

# Buy one, get one (BOGO)

Buy a unit and get a second free. The price of one order pays the costs of two units, so it works out as a 50% discount on a two-pack.

## In plain words

Buy one, get one free gives the customer a second unit at no charge. It is among the strongest offers a brand can show, because free reads as more generous than half off.

In money it is the same as 50% off two units. The customer pays for one and you ship two, with both product costs and an extra pick. Whether it works depends almost entirely on how much the product costs relative to its price.

## Formula

- BOGO margin = price of one unit − cost of two units − one order's fulfilment and fees

## Worked example

Buy one $40.00 bag, get one free. The customer pays $40.00 and the order carries $24.00 of product. The engine puts its margin at $3.16, or 7.9%, against $15.36 for the bag sold alone.

To earn the same per visitor, the offer would need 386.1% more buyers.

### The example order

A $40.00 bag of coffee, shipped free, every cost counted

Revenue $40.00 to contribution margin $15.36 (38.4%)

Revenue

$40.00

Cost of goods

−$12.00

Pick and pack

−$1.18

Packaging

−$0.50

Shipping label

−$7.50

Card fee per order

−$0.30

Refunds

−$2.00

Card processing

−$1.16

Contribution margin

$15.36

2 declared kinds cost nothing on this option

Computed by the margin engine in Offer Suite's own code, in whole cents, from a $40.00 bag of coffee with a $12.00 unit cost.

## BOGO is not two sales

It is one order with one payment. Counting the free unit as a second sale at full price doubles revenue that never existed. The free unit is a cost of the order, like a gift.

## Using it

Keep it for products with a very low unit cost against their price, for clearing stock that would otherwise be written off, or for a first purchase you expect to lead to many more. On a product with ordinary margins it turns a profitable order into a near break-even one, so run the numbers before the banner goes up.

## Related

- [Glossary **Glossary of offer economics** The terms behind offer profit, defined plainly with their formulas and a worked number: contribution margin, profit per visitor, break-even lift and more.](https://offersuite.io/glossary)
- [Calculator **Gift with purchase profit calculator** What a free gift costs per order, after its unit cost, its extra pick and its handling, and how much conversion it has to add to pay for itself.](https://offersuite.io/calculators/gift-with-purchase-profit)
- [Calculator **Bundle pricing calculator: shipping, subscriptions** Price a bundle against a single unit, one-time and subscribed, with the shipping and pick costs it saves, and the conversion it can lose and still earn as much.](https://offersuite.io/calculators/bundle-pricing)
- [Glossary **Gift with purchase: definition, formula and example** A free item added to an order to win the sale. It leaves the price alone and adds a unit cost, a pick and sometimes a heavier parcel.](https://offersuite.io/glossary/gift-with-purchase)
- [Glossary **Percentage discount: definition and formula** A share taken off the price. It comes off revenue in full while most costs stay put, so it removes a much larger share of the margin.](https://offersuite.io/glossary/percentage-discount)
- [Glossary **Product bundle: definition, formula and example** Several units sold together at one price, usually below the sum of their prices. It earns more per order because the units share one label.](https://offersuite.io/glossary/product-bundle)